The invention relates to a method for constant-current generation and device used to carry out said method.
Electrical power generators, in particular those that produce electrical power from internal combustion engines, are known, for example generators whose output frequency has a fixed relationship with the rotational speed of the drive. Known in particular are electrical power generators which operate at a constant rotational speed. In the case of smaller generators having permanent-magnet excitation and a d.c. intermediate circuit, attempts to achieve a constant voltage independently of rotational speed have usually involved the use of parallel regulators, in the case of which any excess power generated was converted into thermal losses/energy, i.e. was wasted.
In this regard a combined motor/generator system for generating electrical power for single-phase emergency power supply systems has been disclosed, for example, by HONDA, in which an external rotor of a generator was integrated in an internal combustion engine, with the result that savings could be made in terms of costly generator shafts and generator components. This known system was disadvantageous, however, in that it always required a specially designed and adapted internal combustion engine as the energy source. This construction also does not satisfy stringent protection class requirements—i.e. it is not suitable for use in certain environmental conditions, such as outdoor use subject to weathering conditions or else in areas of high humidity or in areas in which a high protection class is required by law, for example by fire services, technical assistance organizations, field hospitals, etc.
One object of the invention is therefore to specify a method for generating electrical power which enables a current level which is independent of rotational speed for a wide range of input rotational speeds.